Communication and Perception

Sharks have several highly developed senses. Their primary sense is the ability to smell. They can detect a drop of blood in 100 liters of water. They also have the ability to detect electrical charges as small as 0.005 microvolts. Prey can be detected by the electrical field generated by a beating heart or gill action. Fish in hiding can also be detected this way. At feeding aggregations, such as at whale carcasses, this generally solitary species often establishes temporary social hierarchies which are based largely on size. Among similar-sized individuals, the social hierarchy is maintained through a subtle form of body language. Recent research has demonstrated that great whites are socially complex, featuring such behaviors as parallel swimming, jaw gaping, pectoral fin depression, and even splash-fights. Great white sharks are also unusual among sharks in that they sometime rais their heads out of the water, apparently to observe activity above the surface. (Aidan Martin, 2003; Dale, 2008)